Patent GB-1170403-A (GB)
Title: Improvements relating to Audio-Visual Apparatus
IPC: G03B21/10
Filed: 1968-04-11
Abstract: 1,170,403. Audio-visual reproducing apparatus; teaching appliances. COLUMBIA BROADCASTING SYSTEM Inc. 11 April, 1968 [13 April, 1967], No. 17535/68. Headings G5G and G5R. An audio-visual holder for use with an audio-visual reproducing device comprises an annular transparent disc having a central bore, a movable storage medium having sound information recorded thereon retained within the bore, spaced visual information segments circumferentially mounted in the transparent disc in groups, and means for retaining each group of such segments stationary in the disc. The invention also includes a reproducing device which incorporates various means for advancing the holder stepwise and locating it to align visual parts with optical projection means, and for driving the audio part independently for reproduction of sound therefrom; the reproducing device also includes control means responsive to the information reproduced from the storage medium for controlling the actuation of the above-mentioned advancing and driving means. The complete holder or cartridge 54 is shown in Fig. 7 (underneath view). In Fig. 3 the cartridge is represented by the parts indicated by alternate heavy and light cross-hatching and is shown with the record disc 58 separate from, but still captive within, the transparent disc structure 59, 60. Teaching; manual mode.-A loading lever 84, Figs. 1 and 2, is rotated clockwise to release locking arms 108, 114. When the cartridge 54 is inserted in a slot in the front of casing 10 it pivots the locking arms about their pivots 126. When the loading lever 84 is rotated back again, the locking arms are forced down on to the cartridge in the position shown in Fig. 3. The disc structure 59, 60 now rests on an annular ratchet 164 which is urged upwards by a spring 165, whose hub 166 is rotatable about a shaft housing 152; ratchet 164 and disc 59 are aligned by a pin 170 engaging an opening 83 (see also Fig. 7). The record disc 58 has been retained above disc 59 by a turntable 142, 144, which is cleared by the bore 61 in disc 59. The power supply to a projection lamp 210, Fig. 3, to the drive mechanism (not shown or described) of a tone arm 96, Fig. 3, and to control circuitry (not shown) is switched on by return of lever 84. For this mode, the record disc 58 contains teaching information. A button 34, Fig. 1, is actuated to the " teach " position, the " M " side of an automaticmanual switch 38 is depressed, and an " advance " push-button 39 is depressed. This causes a " ready " lamp 44, Fig. 1, energized at switch-on, to be extinguished. At the same time a motor 160, Fig. 3, driving turn-table 142, is energized, and a solenoid 174, Fig. 3, is energized momentarily. The solenoid operates an engagement pawl 190, which has an upturned flange 192 which engages one of teeth 172 in the edge of ratchet 164, to move disc 59 through an angular distance equivalent to one transparency 56. A projection system 210 to 222, Fig. 3, then projects an image of the appropriate transparency on to an opaque front projection screen 28, Fig. 1, via a mirror 224 in a cover 30, Figs. 1 and 3, while the tone arm 96, Fig. 3, is lowered on to record disc 58 and driven partly across it to reproduce a segment of the audio recording at loudspeaker 47 or headset jack 48, Fig. 1. At the end of this audio segment, a recorded inaudible tone signal is sensed by the stylus 236, separated by a tone signal separator in the circuitry, and applied to a relay which de-energizes turntable motor 160 and re-energizes the " ready " lamp 44. To project the next transparency and reproduce the next audio segment, the operator presses button 39 again. Teaching: automatic mode.-After the button 34 is actuated to the " teach " position, the left-hand side "A" (instead of the side "M") of the automatic-manual switch 38 is depressed, and the "advance" " push-button 39 is depressed as before. In this case, after the projection of the first transparency and the reproduction of the first segment of the audio recording, the apparatus continues to operate, the turn-table motor 160 remaining energized; also, in this case, the tone signal at the end of the first audio segment is used to effect the momentary energization of the solenoid 174 to advance the next transparency into position for projection, after which the second audio segment is reproduced, and so on. Lamp 44 remains extinguished. Test mode.-For this mode, the record disc 58 has recorded on it questions about the projected transparencies, each question being presented as a three-element multiple choice. In this case, after loading of the cartridge, the button 34 is actuated to " test " position. This renders switch 38 and button 39 ineffectual, but lamp 44 is energized. The testing operation is initiated by depressing any one of three " answer " switches 40, 41, 42, Fig. 1. Thereafter the operation is the same as the manual teaching mode, except that a question is put to the operator. At the end of the first audio segment the turn-table motor is de-energized and the " ready " lamp 44 again lights. The operator must now answer the question by depressing whichever of the three answer switches 40 to 42 he thinks appropriate. Each switch is in series with one of three microswitches 76 to 80, Fig. 7, which co-operate with selectively-spaced depressions 74 in the underside of disc 59. Only one depression is provided for each transparency, and if the correct answer button is selected, the appropriate microswitch, which is in engagement with the depression, remains open. Accordingly, current is not supplied to an " error " lamp 45, Fig. 1, or an error counter 46. If either of the wrong answer buttons is depressed, the " error " lamp lights, and counter 46 registers. In all cases such depression of an answer button reenergizes the turn-table motor, extinguishes " ready " lamp 44, and advances the next transparency. In a modification, however, a relay is provided to prevent re-energization of the motor and advance of the next transparency if a wrong answer button is depressed. Preferably the " teach-test " button 34 is situated inside a sliding panel which can be opened only by the teacher or other authorized person.